1. FIELD OF THE INVENTION
This invention relates generally to an automatic electro-optical inspection system and, more particularly, to a system including a unique inspection table and a movable yoke which is adapted to ride along the table to automatically document and verify the position and dimensions of holes made in a flat sheet metal workpiece.
2. PRIOR ART
It has been common to manually inspect punched, flat sheet metal workpieces. The conventional manual inspection technique involves using a height gauge, catipers and/or a tape to verify the dimensions of each hole or the position of a hole relative to an edge of the workpiece. Where a multitude of holes may be involved in a large number of workpieces, it becomes a laborious and time consuming task for one or more workmen to manually inspect each hole and provide a record of the inspection results.
Accordingly, automatic electro-optical inspection systems have been proposed to increase the efficiency and lower the cost of inspecting the holes in a flat workpiece. However, such automatic systems usually involve the complex movement of the workpiece. More particularly, a pair of motors and associated position monitoring apparatus are frequently used to either rotate the workpiece or move the workpiece in each of a pair of perpendicular directions. Such a system is generally slow and expensive and requires relative lengthy calculations to document and verify the size and location of the hole.
Examples of known systems for inspecting holes in a flat workpiece are available in one or more of the following U.S. Pat. Nos. 2,684,009, July 20, 1954, 4,319,272, Mar. 9, 1982, 4,555,798 Nov. 26, 1985 4,560,273, Dec. 24, 1985.